<div class="layui-form-item">
<label  class="layui-form-label">{$field.alias}</label>
    <div class="layui-input-block">
        <select name="{$field.name}" class="layui-input">
        {foreach $field.optional_data_arr as $k=>$v}
            <option value="{$k}">{$v}</option>
        {/foreach}
        </select>
    </div>
</div>